What Are Standard Mylar Bag Thicknesses? 

What Is Mylar?

Mylar is a brand name for a type of plastic film made from Biaxially Oriented Polyethylene Terephthalate (BoPET)—a strong and durable material that provides an effective barrier against moisture, air, and light. This makes Mylar bags ideal to keep food fresh and retain its quality, among other uses such as storing clothing, documents, and electronics.

Mylar bags are offered in different thicknesses, and what will be ideal for you depends on the kind of food, the length of storage time, and the conditions in which the bags are kept.

Standard Mylar Bag Thickness

Mylar bags are made in a variety of thicknesses and are generally measured in mil (one-thousandth of an inch) or micron (micrometer). The following are the common thicknesses of Mylar bags:

3.5 Mil Mylar Bags

The 3.5 mil thickness is one of the most commonly used food storage options. These bags provide decent light, moisture, and air resistance and are well-suited for non-perishable items like grains, beans, dried fruits, and other similar products for short-term storage. These bags balance flexibility and strength, making them ideal for everyday food storage.

5 Mil Mylar Bags

A little thicker than the 3.5 mil bags, the 5 mil Mylar bags are more durable and puncture-resistant. Many people use these for bulk food storage, such as rice, flour, and freeze-dried meals. The extra thickness provides additional protection against environmental elements. The increased durability helps prevent tears or punctures during handling or storage, making them a top choice for long-term storage in harsher conditions.

7 Mil Mylar Bags

The 7 mil thickness is typically the best for long-term, high-security food storage. These bags offer better protection against physical damage, moisture, and light degradation. Common uses include foods that require long-term preservation, such as bulk grains, emergency rations, and freeze-dried meals. The 7 mil bags are tough enough to handle temperature fluctuations and rough handling, making them suitable for long-term storage.

10 Mil Mylar Bags

For specialized needs, 10 mil Mylar bags are available. These ultra-thick bags are generally used in industrial applications but can be helpful for particularly sensitive or highly valuable foods that require extra protection. These bags offer the highest level of protection against punctures and tears, making them ideal for products stored in extreme environments or for foods that will undergo frequent handling. Although not common for everyday home storage, 10 mil bags are perfect for extremely long storage or products that are frequently moved.

Choosing the Right Thickness of a Mylar Bag for the Job

The choice of the right thickness will depend on the food, the expected duration of storage, and the conditions under which the products will be stored. Here’s how to select Mylar bag thickness based on several factors:

Duration Intended for Storage:

For long-term storage, a 5 mil or thicker Mylar bag is preferable. These thicker bags offer increased protection against moisture and air seepage over extended periods. Additionally, they provide better puncture resistance, which makes them ideal for food that will be stored for several years.

Food Type:

Thicker Mylar bags add an extra layer of protection for moisture-prone foods like freeze-dried meals and powdered foods. Other food items like grains, beans, and pasta can be stored in 3.5 mil or 5 mil bags, as they are more resilient to typical storage conditions.

Environmental Conditions:

If your food will be stored in environments subjected to rough handling, temperature changes, or high humidity, a 7 mil or 10 mil bag will provide more security. These are excellent options if your food will be exposed to potential punctures or tears.

Handling and Transport:

Thicker bags are required for foods that will be frequently handled or moved to prevent tears or damage. 7 mil or 10 mil bags are ideal for these situations, especially if the bags will be stored in less-than-ideal conditions or if they will be frequently moved.

Other Considerations When Using Mylar Bags

• Oxygen Absorbers:
  Oxygen absorbers are essential when using Mylar bags for food storage. They remove any residual oxygen inside the bag, which helps prevent spoilage. Always include the appropriate amount of oxygen absorbers based on the bag size and type of food stored.
• Sealing:
  Proper sealing is critical for ensuring the food inside lasts longer. A strong airtight seal can be made using a heat sealer. The seal should be perfect to prevent air and moisture from entering the bag. Any gap or breach in the seal will compromise the longevity of the food.
• Storage Location:
  After sealing Mylar bags, store them in a cool, dry, and dark location. Ideal storage conditions include a temperature range of 50 to 70°F (10 to 21°C), away from direct sunlight and humidity. If storing a large quantity of food, consider using plastic buckets for additional protection against light and potential damage.

Conclusion: Choosing the Right Mylar Bag Thickness

The thickness of a Mylar bag is crucial in ensuring the longevity and freshness of the food stored inside. Whether you’re storing grains, freeze-dried meals, or dehydrated vegetables, understanding the different Mylar bag thicknesses will help you make an informed choice based on your needs. Thicker bags provide better protection, while thinner bags are suitable for food items that need to be consumed sooner or under less demanding conditions.